If you follow the link to the actual license, it does list done explicitly permitted uses. So yes, it does seem that you can fork it and do something useful wit

If you follow the link to the actual license, it does list done explicitly permitted uses. So yes, it does seem that you can fork it and do something useful with the fork. That something useful is restricted, which is the point of the license. I think the intention here is reasonable and honest as presented by the big list. Whether the actual legal language matches that intention - who knows. I'm worried that it might not but IANAL.